The Bulletin’s coverage of these events and many other aspects of the modern nuclear dilemma was truly comprehensive last year. What follows, then, is not a “best of” list, per se, but eight prime examples from the remarkably consistent and excellent offerings our expert authors provided throughout the year. I thank and applaud them all.

A comprehensive look at the meaning, in today’s world, of a landmark TV movie, including an interview with Ted Koppel, who led an expert panel discussion after the airing of a film that changed world nuclear history.

A collection of extraordinary experts assesses the import of the Trump administration’s declared interest in leaving the landmark Intermediate-range Nuclear Forces Treaty, a foundation of the world’s arms control regime.

One of the premier experts on the US nuclear weapons complex explores an Energy Department attack on the Defense Nuclear Facilities Safety Board, which oversees and reports on safety practices in the complex.

Through the decades, the Bulletin has been home to distinguished analysis of the US atomic bombing of two Japanese cities at the end of World War II. This collection provides an authoritative starting point for anyone interested in understanding the lasting meaning of those attacks.

Moscow has reportedly begun testing an underwater nuclear weapon that has been touted as invincible by Russian President Vladimir Putin.

The Poseidon, previously known as the Status-6 Oceanic Multipurpose System and dubbed Kanyon by the U.S.-led NATO Western military alliance, is a state-of-the-art nuclear-capable drone being developed by the Russian armed forces. Citing a defense industry source, the state-run Tass Russian News Agency reported Tuesday that the Russian navy had begun trails for the weapon at sea.

“In the sea area protected from a potential enemy’s reconnaissance means, the underwater trials of the nuclear propulsion unit of the Poseidon drone are underway,” the source said, according to the official outlet.

Russia’s nuclear-capable “doomsday” drone, named Poseidon by Russia and Kanyon by the U.S., is seen in this simulation played by Russian President Vladimir Putin during his state of the nation address, on March 1. RUSSIAN MINISTRY OF DEFENSE

The Poseidon’s true power has never been revealed, but rumors of its existence have swirled among defense circles for years. In September 2015, The Washington Free Beacon cited Pentagon sources as saying Russia was developing submarines armed with “Kanyon” nuclear-capable drones dubbed “city busters,” with “tens” of megaton explosive power and capable of traveling long distances at high speeds. Two months later, Russian state media outlet NTV showed blueprints of a nuclear-capable underwater drone, titled “Status-6 Oceanic Multipurpose System,” while covering a meeting of officials.

Putin revealed the drone’s existence during his State of the Nation address in March, along with an arsenal of other advanced weapons said capable of thwarting even the most modern defense systems—and many of which were capable of being fitted with nuclear warheads. At the time, he said that Russia had completed its development of “an innovative nuclear power unit” 100 times smaller than existing submarine reactors, but still more powerful and capable of hitting its maximum capacity 200 times faster, while carrying “massive nuclear ordnance.”

“We have developed unmanned submersible vehicles that can move at great depths (I would say extreme depths) intercontinentally, at a speed multiple times higher than the speed of submarines, cutting-edge torpedoes and all kinds of surface vessels, including some of the fastest,” Putin told his federal assembly in March. “It is really fantastic. They are quiet, highly maneuverable and have hardly any vulnerabilities for the enemy to exploit. There is simply nothing in the world capable of withstanding them.”

The Poseidon received its name later that month after the Russian Defense Ministry held a poll in which users also dubbed the Peresvet laser weapon system and 9M730 Burevestnik nuclear-powered cruise missile.

A number of reports have claimed that the weapon may be capable of producing massive, radioactive tsunamis that would pose a threat to major cities. Some experts have corroborated this theory, although they have questioned the tactical effectiveness of this strategy.

Russia has set out to modernize its strategic and conventional arsenal in response to a perceived threat posed by the U.S. military dominance and development of a global missile shield made possible by Washington’s withdrawal of the Anti-Ballistic Missile (ABM) treaty in 2001. President Donald Trump has since threatened to pull out of the Intermediate-range Nuclear Forces (INF) treaty banning land-based missile systems ranging from 310 to 3,400 miles, while Moscow has claimed that the Trump administration has not responded to offers to start talks regarding the renewal of the New Strategic Arms Reduction Treaty (START).

Washington has accused the Kremlin of attempting to influence the 2016 U.S. presidential election in Trump’s favor, something Putin and his officials have denied. Though the Republican leader set out to rebuild deteriorating ties between Washington and Moscow upon coming to office, the U.S. has since expanded sanctions against Russia and relations have only worsened between the two leading powers.

The abrupt and pointed resignation of Secretary of Defense Jim Mattis on Thursday alarmed official Washington. Sen. Mark R. Warner, D-Va., called him an “an island of stability amid the chaos of the Trump administration.” Retiring Sen. Jeff Flake, R-Ariz., told The Washington Post that “having Mattis there gave all of us a great deal more comfort than we have now.”

Mattis’ departure seems to be provoking unease, especially considering how dangerous our nuclear-command arrangements are. The notion that Mattis, a former four-star Marine Corps general, could have blocked or defied a move by Trump to impulsively launch nuclear weapons may have seemed comforting, but it shouldn’t have been. The secretary of defense has no legal position in the nuclear chain of command, and any attempts by a secretary of defense to prevent the president from exercising the authority to use nuclear weapons would be undemocratic and illegal. With or without Mattis, the president has unchecked and complete authority to launch nuclear weapons based on his sole discretion.

The reaction to Mattis’ resignation, however, could open the door for the new Congress to create long-overdue legal barriers preventing the president from initiating a nuclear strike. Such a step could be implemented without any negative impact on U.S. security or that of our allies.

Every day, the U.S. nuclear early warning system is triggered by some event or another, mostly civilian and military rocket launches by one or more of a dozen countries with ballistic missiles. When such launches appear to threaten North America, the head of U.S. Strategic Command is alerted, and sometimes these alerts warrant the urgent notification of the president. That alert comes by way of a direct call from the Strategic Command or via the White House Situation Room, the emergency-operations bunker beneath the East Wing, or the national security adviser. Partly a remnant of the Cold War, this system remains in place today to ensure the president can be notified quickly of any direct threat to the United States’ nuclear arsenal and the facilities that control it. That way, he can launch nuclear missiles before they are destroyed or the U.S. government is incapacitated by incoming weapons.

In normal times, this system is precarious, and it can pressure even experienced leaders to consider nuclear weapons in a crisis sooner than warranted. Alerts stemming from ambiguous ballistic nuclear missile threats occurred multiple times during the administrations of George W. Bush and Barack Obama, and some alerts went directly to those presidents.

Yet, this system seems especially ill-suited to a president who has demonstrated time and again that he can be provoked into taking rash action, and who, as a candidate, openly questioned why the United States could not use the nuclear weapons it possesses. This is a dangerous set of instincts for a commander in chief with sole and unchecked authority over almost 4,000 nuclear weapons, nearly 1,000 of which could be fired within a few minutes.

For over a year, Mattis has been trying to reassure congressional leaders that he could help check some of Trump’s impulses, in part by intervening in the nuclear chain of command. In a break with normal procedures, Mattis reportedly told the commander of the Strategic Command to keep him directly informed of any event that might lead to a nuclear alert being sent to the president. He even told the Strategic Command “not to put on a pot of coffee without letting him know.”

Congressional leaders interpreted this to mean that Mattis would either deal with a possible threat before it reached Trump or ensure he was present to advise Trump when such an alert arrived.

This assurance may have helped ease concerns about our nuclear weapons for some members of Congress, but only if they were unfamiliar with how the command and control structure truly works. Personal relationships and back channels are no way to manage a nuclear arsenal.

Under standard procedure, an attempt would be made to contact key national security officials, but in some real-world and exercise scenarios, it has proven impossible to tie them into a quickly convened emergency teleconference. Should he wish, the president could exclude all of them, and even bypass the primary designated adviser – the four-star general in charge of U.S. strategic forces – by ordering a low-ranking on-duty emergency operations officer at the Pentagon or elsewhere to transmit a launch order directly to the executing commanders of strategic U.S. submarines, silo-based missiles and bombers.

Trump could have learned all this in a briefing about nuclear weapons shortly after he took office, and his military aide, ever at his side, could explain and assist in issuing a direct order to a lower-level officer at any time.

Even if Mattis had been with Trump at a time of nuclear crisis, his resignation letter drives home the fact that Trump might very well have simply ignored his counsel. Trump, as he is proving in stark terms, listens only to himself. And any attempt by another person to physically block the president from issuing a launch order would probably result in his or her removal by the Secret Service. It is delusional and fundamentally undemocratic to think that our strongest check on a president bent on initiating nuclear war without justifiable cause might be a defense secretary trying to keep the president from communicating his launch authority using the so-called Gold Codes.

When the United States faced the prospect of sudden nuclear attack from the Soviet Union, this system helped reinforce deterrence based on a balance of nuclear terror. But since the demise of the U.S.S.R., and even with a more aggressive Russia, the whole arrangement raises questions about its necessity, risks and consistency with democratic values. It is well past time for the system to be reformed to ensure that it hews to our Constitution and mitigates as much as possible the very real risks associated with a renewed arms competition with Russia.

One key issue is whether Trump – or any president – should have the legal ability to independently initiate the use of nuclear weapons. It seems reasonable that the president needs to be able to quickly order a nuclear response if an adversary employs nuclear weapons first against us, and that he would not have time to consult with Congress or the Cabinet if nuclear missiles were headed here. (The flight time of ballistic missiles over intercontinental distances is 30 minutes or less, and the president would have only about five to seven minutes to decide whether and how to respond.)

However, our chain of command is not just a presidential preference – it can be determined by legislative action. Congress can and should prohibit any president from using nuclear weapons first. The incoming chairman of the House Armed Services Committee, Rep. Adam Smith, D-Wash., proposed such legislation last year. It states that it is the policy of the United States not to be the first to use nuclear weapons. Congress could make any first-use illegal, constraining the president from issuing such an order and obligating any member of the military to disobey a command to do so. A no-first-use policy would also ratchet down tensions with Russia and facilitate reductions in the number and types of nuclear weapons in both U.S. and Russian arsenals. The logic and political salience of this position is growing, with some 20 members of the incoming Congress – including House Speaker-to-be Rep. Nancy Pelosi, D-Calif. – now on record supporting no first use.

Legislation to bar first use probably wouldn’t get through the Republican Senate or be signed into law by Trump. But recognition that the system puts too much power in the hands of one person increases the likelihood that the next president will either adopt such a posture or accept legislative controls. Maintaining an outdated and unstable system is clearly too dangerous.

Bending norms and the military chain of command to prevent a disastrous presidential decision is not a reliable safeguard, and extralegal measures should not be how the United States prevents a nuclear war. Neither Mattis nor anyone else can reassure the American people that a president will not, on a whim, use the most fearsome weapons humans have ever invented. Only laws can constrain such a dangerous prospect. It is well past time for our country to take control of the nuclear chain of command.

—

Blair is a research scholar in Princeton University’s Program on Science and Global Security and a founder of Global Zero, the international movement for the elimination of nuclear weapons.

Wolfsthal is a former senior director at the National Security Council for arms control and nonproliferation. He is now a senior adviser to Global Zero in Washington.

Russia said on Saturday that the scrapping of a Cold War era nuclear pact may lead to an arms race and direct confrontation between several global regions, after a proposal by Moscow was rejected in a United Nations vote.

Moscow had put forward a resolution in support of the 1987 Intermediate-range Nuclear Forces Treaty which bans Moscow and Washington from stationing short- and intermediate-range, land-based missiles in Europe.

Russia’s foreign ministry said in a statement that the UN had failed to vote in favor of the proposal.

“A new blow has been dealt on the global architecture of security and stability. Now, with the collapse of the INF treaty, several global regions could be plunged into the arms race or even into a direct confrontation,” it said.

On Thursday, Russian President Vladimir Putin accused the United States of raising the risk of nuclear war by threatening to spurn the key arms control treaty and refusing to hold talks about another pact that expires soon.

He pointed at Washington’s intention to walk away from the 1987 Intermediate-Range Nuclear Forces Treaty, or INF, and its reluctance to negotiate the extension of the 2010 New START agreement, which expires in 2021 unless the two countries agree to extend it. “We are witnessing the breakup of the arms control system,” he said.

Moscow and Washington have been at loggerheads over the INF, which bans an entire class of weapons — all nuclear and conventional ground-launched ballistic and cruise missiles of intermediate range. U.S. officials say Washington’s withdrawal from the pact was prompted by Russian violations of the treaty, which Moscow vehemently denies.

Earlier this month NATO, at U.S. request formally declared Russia to be in violation of the INF and demanded that it halt activity that breaches it. The move put the full weight of the alliance behind the U.S., which has given Russia until February to come into compliance or trigger Washington’s withdrawal from the treaty.”

Officials in both Russia and the U.S. have given mixed signals about the future of the New START treaty, signed by President Barack Obama and then-Russian President Dmitry Medvedev amid a brief thaw in Russia-U.S. ties. U.S.-Russian strategic nuclear weapons — those capable of striking each other’s territory — are governed by New Start.

During the nearly four-hour news conference, Putin maintained Russia was not interested in “gaining unilateral advantages. We aren’t seeking advantages, we are trying to preserve the balance and ensure our security.”

The U.S. and European nations have repeatedly called out Russia and imposed sanctions on it for its support of separatists in eastern Ukraine and its annexation of Crimea in 2014. At the same time the West has harshly criticized Russia for its military and political support for Syrian President Bashar Assad, which U.S. officials say has prolonged the war in Syria and the suffering of its people.

The Russian leader scoffed at the allegations, rejecting them as part of a smear campaign driven by domestic policy in the U.S. and elsewhere in the West.

He dismissed claims that Russia is interfering abroad, from a nerve agent poisoning in Britain to an alleged effort to infiltrate the U.S. National Rifle Association, charging that those accusations are part of U.S.-led efforts to malign Russia to strengthen the Western allies’ unity.

“They need an external threat to cement NATO unity,” Putin said, accusing the U.S. and its allies of exploiting “phobias of the past” to achieve domestic political goals.

“As for ruling the world, we know where the headquarters trying to do that are located, and the place isn’t Moscow,” he said, noting that the Pentagon’s annual budget of over $700 billion dwarfs Russia’s defense spending of $46 billion.

Russia’s hopes for repairing ties with the U.S. under President Donald Trump have fizzled amid the allegations of Russian meddling in the 2016 election — charges Putin has denied.

He noted that he’s still keeping the door open for a meeting with Trump, but added that the prospect for that looks increasingly dim in view of the Democrats winning control of the House.

“You can predict new attacks on the president with 100-percent probability,” Putin said. “I don’t know if he could engage in a direct dialogue with Russia in such conditions.”

He charged that that the continuing U.S. political infighting reflects a “lack of respect for the voters” who elected Trump. “They don’t want to acknowledge his victory and do everything to delegitimize the president,” Putin added.

He insisted that a Russian woman in U.S. custody has not carried out any mission for the Russian government, even though she pleaded guilty this month to acting as a covert agent of the government. Putin claimed that Maria Butina — accused of trying to infiltrate the NRA and American conservative circles around the time of Trump’s election — entered the guilty plea because of the threat of a long prison sentence in the case, which Putin described as fabricated.

The U.S. “has done the right thing,” Putin said, reaffirming the long-held Russian argument that the U.S. presence in Syria is illegitimate because it wasn’t vetted by the U.N. Security Council or approved by Syrian President Bashar Assad’s government. The pullout is also likely to strengthen Russia’s role in Syria’s future.

He showed no sign of backing down from Russia’s stance on Ukraine, accusing his Ukrainian counterpart of provoking a naval standoff with Russia to boost his electoral prospects. The Russian coast guard fired upon and seized three Ukrainian naval vessels and 24 seamen when they tried to sail from the Black Sea into the Sea of Azov in what the U.S. and its NATO allies condemned as unjustified use of force by Russia.

Turning to nuclear weapons, Putin warned that if the U.S. puts intermediate-range missiles in Europe after its planned exit from the INF Treaty banning them, Russia will be forced to take countermeasures.

As for what he described as U.S. reluctance to extend the New START nuclear arms reduction treaty, he said: “You aren’t interested? You don’t need it? OK, we will survive. … But it will be very bad for the whole of humankind, because it would take us to a very dangerous area.”

Addressing his ministry’s annual defense board meeting Tuesday, Russian Defense Minister Sergei Shoigu said that over 18,000 exercises and training sessions were conducted in the past year and that new ones are being planned for 2019. These included the strategic command and staff drill called Center-2019 and the strategic forces Thunder exercise, both designed to test the country’s ability to unleash nuclear attacks, if necessary.

“The Strategic Nuclear Forces are maintained at a level that makes it possible to guarantee nuclear deterrence,” the ministry said in a readout of the meeting. “The task set out in 2017 to bring the Strategic Nuclear Forces to a level of 82 percent modernization has been completed.”

According to the ministry, Shoigu noted that “in contrast to the U.S. deployment of a global missile defense system, the armed forces are increasing their strike potential.” He touted the addition of new strategic carriers for air, land and sea, as well as the development of new nuclear-capable weapons such as the RS-28 Sarmat intercontinental ballistic missile, the Avangard hypersonic glide vehicle and the Kinzhal hypersonic air-launched missile, which were “all guaranteed to overcome the most modern anti-missile systems.”

Both President Donald Trump and Russian President Vladimir Putin have sought to modernize their nuclear arsenals, the scopes of which have been limited by arms control agreements such as the 1987 Intermediate-Range Nuclear Forces (INF) treaty and the 2010 New Strategic Arms Reduction Treaty, itself a renewal of the earlier START signed between the U.S. and Soviet Union in 1991.

In 2014, however, Washington first accused Moscow of violating the INF through its development of the Novator 9M729 missile system, said to fall within the restricted 310- to 3,400-mile range for land-based nuclear and conventional weapons. Russia has denied this and instead charged the U.S. with breaking the agreement by installing defensive missile systems that could allegedly be used to attack as well.

The Trump administration announced in October that it intended to withdraw from the INF and has reportedly refused to begin negotiations on renewing the New START, which expires in 2021. Putin has vowed to respond by working to “restore balance” in the military sphere and warned during Tuesday’s Russian Defense Ministry meeting that a U.S. exit from the INF “will have the most negative consequences and will noticeably weaken regional and global security.”

“In fact, in the long term, we can talk about the degradation and even collapse of the entire architecture of arms control and the nonproliferation of weapons of mass destruction,” Putin said. “We will be forced to take additional measures to strengthen our security.”

With Russia’s new nuclear-capable weapons said to have demonstrated unprecedented capabilities, Putin added that he hoped those who “got accustomed to militaristic rhetoric” would now be made to “think.” The words echoed his previous speech in March, when—upon revealing his country’s new “super weapons”—he warned rivals who dismissed Russia as a world player that “you will listen to us now.”

Though the U.S. maintains a sizable lead over Russian military power, Putin has sought to close this gap by increasing his country’s strategic offensive prowess and by seeking closer regional relations with countries such as China, India and Pakistan. Russian senators have also reportedly considered easing the country’s nuclear doctrine in response to growing tensions with the Trump administration and its own nuclear vision.

Neither Russia nor the U.S. has agreed to maintain a “no-first-use” policy, and both countries reserve the right to use nuclear weapons pre-emptively.

There has been a “fragile bipartisan consensus” on nuclear weapons, according to Frank Rose, a senior fellow for security and strategy at the Brookings Institution.

During the Obama administration, a deal was brokered under which Republicans supported the New START treaty to reduce nuclear weapons while Democrats backed the modernization of the U.S.’ nuclear arsenal, he said.

Without the arms-control treaties, Democrats could block the funding of nuclear weapons in the 2020 budget with their new majority in the House.

“They can’t build a consensus to do something new or different — the Senate or president might not go along — but they can stop things from happening,” Tom Collina, director of policy at the Ploughshares Fund, which is focused on reducing nuclear weapons. “The power of ‘no’ is a significant force.”

Rep. Adam Smith, D-Wash., is expected to be the new chair of the House Armed Services Committee and he has been vocal about stopping runaway defense spending.

But while controversial, over-budget programs like Lockheed Martin‘s (LMT) F-35 still grab headlines, the new stealth fighter must replace an aging fighter fleet, and hundreds have already been produced.

By contrast, efforts to modernize U.S. nuclear weapons are still at a relatively early stage. And Democrats have always been more skeptical of nuclear programs, said Mark Cancian, a senior advisor at the Center for Strategic and International Studies.

Nuclear Weapons That May Go Boom Or Bust

To modernize the air-based leg of the nuclear weapons triad, the Air Force awarded the B-21 contract to Northrop Grumman (NOC) in 2015 to replace Cold War-era Boeing (BA) B-52s. The eventual procurement price tag is estimated at $80 billion.

The Air Force awarded the B-21 contract to Northrop Grumman in 2015 to replace Cold War-era B-52s.

Cancian believes that this new stealth bomber will survive upcoming procurement battles because of its ability to deliver conventional munitions as well.

New Columbia-class ballistic missile submarines will modernize the sea-based leg of the nuclear triad and replace Ohio-class “boomers.” General Dynamics‘ (GD) Electric Boat is building them with total acquisition costs expected to hit $128 billion.

Cancian also believes that the Columbia-class submarine program will continue, saying ballistic subs are most likely to survive a nuclear attack because they are hidden underwater.

Then there are two missile programs without contract awards yet that have been more controversial. Lockheed and Raytheon (RTN) are competing for the Long-Range Standoff weapon (LRSO), a nuclear cruise missile to be launched from strategic bombers.

Former Defense Secretary William Perry and retired Gen. James Cartwright, former vice chair of the Joint Chiefs, argued last year that ICBMs and nuclear cruise missiles carry greater risks of accidentally setting off a nuclear war because they can’t be recalled once launched.

General Dynamics is building Columbia-class subs with total acquisition costs expected to hit $128 billion.

Canceling them would also save billions of dollars that could be used for other pressing national security needs, they said. Meanwhile, nuclear subs and bombers would provide sufficient deterrence and aren’t vulnerable to a surprise attack, allowing them to wait out an alarm that may end up being false.

But Defense Secretary James Mattis has backed the development of new ICBMs and the need for a complete triad as near-peer competition against China and Russia heats up.

Meanwhile, a Congressional Budget Office report on how to reduce the deficit found that canceling the LRSO program and the nuclear warheads associated with it would save $13 billion over the next 10 years, with savings to continue after 2028.

Collina at the Ploughshares Fund said that Rep. Smith could go after the estimated $85 billion-$100 billion GBSD program or $20 billion LRSO, to “make a case that he’s actually saving money.”

High Anxiety Over Low-Yield Nuclear Weapons

The U.S. already has about 500 low-yield airdropped nuclear weapons in its arsenal. And Smith is extremely critical of the low-yield warheads for Lockheed’s Trident D5 submarine-launched ballistic missile.

“It makes no sense for us to build low-yield nuclear weapons,” Smith said at a Ploughshares conference in November. “It brings us no advantage and it is dangerously escalating. It just begins a new nuclear arms race with people just building nuclear weapons all across the board in a way that I think places us at greater danger.”

Because they are less destructive than other nuclear weapons, low-yield warheads could be seen as less risky to use, thereby lowering the threshold for nuclear war, critics like Smith say.

But the Trump administration’s 2018 Nuclear Posture Review argued that low-yield nuclear weapons would raise the threshold for nuclear war.

“Expanding flexible U.S. nuclear options now to include low-yield options is important for the preservation of credible deterrence against regional aggression,” the review said. “It will raise the nuclear threshold and help ensure that potential adversaries perceive no possible advantage in limited nuclear escalation, making nuclear employment less likely.”

Pentagon Budget Uncertainty

Amid the policy and procurement debates, another source of uncertainty on defense spending is coming from Trump himself.

He blasted the current $716 billion Pentagon budget, tweeting earlier this month that it was “crazy.” But days later he reportedly said he wanted to give the Pentagon $750 billion, above the $733 billion the DOD requested.

With readiness concerns, expensive aircraft programs like the F-35 already in the works, and lower recruiting rates also top of mind, Pentagon officials may have to make some tough choices on spending if Trump flip-flops again and seeks a lower defense budget.

FILE – In this file photo taken on Friday, Sept. 12, 2008, Russia’s strategic bomber Tu-160 or White Swan, the largest supersonic bomber in the world, lands at Engels Air Base near Saratov, about 700 kilometers (450 miles) southeast of Moscow, Russia. The Russian military says two of its nuclear-capable strategic bombers have arrived in Venezuela, a deployment that comes amid soaring Russia-U.S. tensions. (AP Photo/Misha Japaridze, File) (AP)

A pair of Tu-160 bombers arrived at Maiquetia airport outside Caracas Monday. The Russian Defense Ministry said they were escorted by Venezuelan fighter jets during part of the training mission on Wednesday to practice interaction.

This has left Moscow furious and fearful that America will once again, as it did during the Cold War, deploy nuclear missiles in Europe. Because of geographic fate, Russia needs ICBMs launched from Russian soil, or launched from submarines, to strike the continental United States. But shorter-range U.S. missiles based in, say, Germany or Poland could reach the Russian heartland.

Viktor Yesin, who commanded Russia’s Strategic Rocket Forces in the 1990s, spoke of Perimeter/Dead Hand during an interview last month in the Russian newspaper Zvezda [Google English translation here]. Yesin said that if the United States starts deploying intermediate-range missiles in Europe, Russia will consider adopting a doctrine of a preemptive nuclear strike. But he also added this:

Zvezda: “Will we have time to answer if the flight time is reduced to two to three minutes when deploying medium-range missiles near our borders? In this version, all hope is only on Perimeter. And for a retaliatory strike. Or was Perimeter also disassembled for parts?

Yesin: “The Perimeter system is functioning, it has even been improved. But when it works, we will have little left – we can only launch those missiles that will survive after the first attack of the aggressor.”

It is not clear what Yesin meant when he said the system has been “improved,” or even exactly what he meant by “functioning.” Perimeter works by launching specially modified SS-17 ICBMs, which transmit a launch signal to regular nuclear-tipped ICBMs in their silos.

David Hoffman, author of “The Dead Hand,” the definitive book on Perimeter, describes Perimeter in this way:

There have been cryptic clues over the years that Perimeter still exists. Which illustrates one of the curiosities of this system, which is that the Soviet Union kept its existence secret from the American enemy whom it was supposed to deter.

What is unmistakable is that Perimeter is a fear-based solution. Fear of a U.S. first-strike that would decapitate the Russian leadership before it could give the order to retaliate. Fear that a Russian leader might lose his nerve and not give the order.

And if Russia is now discussing Perimeter publicly, that’s reason for the rest of us to worry.

Michael Peck is a contributing writer for the National Interest. He can be found on Twitter and Facebook.

One of those airplanes returned Saturday to Anapa, while the three remain on base.

Ilushin-76 cargo planes are used by the Russian Army to deliver outsized or heavy cargo unable to be carried on the ground. The cargo planes are also used for mobilizing large numbers of troops.

The base of the elite unit of the Russia Airborne troops, the 7th Guards Mountain Air Assault Division is located in Novorossiysk, not far from Anapa.

The division’s troop participated in the last round of violence between Ukraine and Russia in August 2014, in addition to the fighting in Syria.

The IL-76 were spotted in the same airbase where the fourth S-400 surface-to-air missile battery was deployed, Fox News has previously reported.

The mobile S-400 missile has a range of up to almost 250 miles and can climb to an altitude of almost 19 miles. It’s intended to bring down a variety of aerial threats, from aircraft to cruise and ballistic missiles.

The apparent troop buildup comes as Ukraine’s defense ministry warned Friday that it will soon send naval ships through the Kerch Strait.

Ukraine has responded to the actions by Russia by introducing martial law for 30 days, a measure Kiev did not take even after Crimea’s annexation and amid large-scale fighting between Ukrainian forces and Russia-backed separatists in 2014-2015.

As part of martial law, Ukraine has beefed up its forces on the border with Russia and called up reservists for training. Ukrainian Defense Minister Stepan Poltorak told reporters on Friday that his country intends to send naval ships through the Kerch Strait soon, saying that “otherwise Russia will fully occupy the Sea of Azov.”